Frederic schmitt



@einen tatrs atrnt @ffice Letters .Pate-nt No. 66,744, dated July G,1867.

IMPROVEMENTS IN ARTIFICIAL LEGS.

'ilje Stlithnlc nient in in iig-cse tctiet iitcut mit nailing pint nftige smite.

T() ALL WHO IT MAY CONQERN:

Be it known that I, Fnnnnnro SCHMITT, of the city of Springfield, in thecounty oSangamon, and State of Illinois, have invented certain new anduseful Improvements in Artificial Legs; and I do hereby declare that thefollowing is a full, clear, and exact-description thereof, referencebeing had to the accompanying drawings, making a part of thisspecification, in whiclii Figure I is a lside view.

Figure II, a detached view oi`-,tl 1e iron knee-joint.

Figure III, a side'view of the ankle-joint detached.

Figure IV, a bottom view of the'anklel-joint detached; also, thefastening of the heclfcorrl.

4Figure V, a front view of ankle-joint detached.

Figure VI, atop View of the spring ofthe toe-joint detached; and

Figure VII, a side view of the same.'

Likeletters or figures refer to the same parts in all of the' gures.-

Heretofore artificial legs have been so complex in their constructionthat when broken or out of order theyl could only be repaired by personsskilled iii thc art of constructing them, so that in effect their usewas confined to large cities, where such mechanics could be found, as byconstant use they soon become disordered,M and are liable to manyaccidents; or else they were made so heavy. and clumsy as to becomparatively valueless, and not worn upon ordinary occasions, or wereentirely dis-carded. The light ones, by reason of their being socomplex, are also very expensive. All of' these cliiii eulties areovercome by me,'as my leg is light, durable,and`

those part's subject to much wear easily replaced by the wearer, andthey can be made by anygood mechanic.Y To enable others skilled in theart to make and use my invention, I will proceed to describe itsconstruction and operation. l I

The parts A B are made of veneering or other thin strips of light, toughwood, with tine, strong linen placed between the layers, secured by glueor other suitablesubstanee, which mak es them light, strong, andsomewhat flexible, and gives them an easy iit to the part of the leg towhich they are attached. They are made in size and length to tit ,theperson for whom they are designed, and for heavy persons three layers ofwood-and three of linen-will be found sufficient, while for lightpersons two of wood and two of linen will give the required strength.The lower endofA iscurved in front soA as to fit into and turn in B,withoutleaving an open space vwhen bent. They are hinged together orpivoted by riveting, or otherwise fastening the bars E to their sides,which bars are connected together by alrule-joint and red, 7, which runsthrough and forms the pivots for both joints. This rod and therule-joints are located centrally, as shown. An India-rubber band', 1,is passed through the openingf of the knee, and down around the end ofA,through a similar opening, h, in the calf of B, where it is Vbuckled atg, or secured, by other adjustable fasteningso that the tension can bevariedfand make the knee-joint very flexible or comparatively rigid, asmay be desired.' This strap 1 forms the spring of `the kneejoint, andwill prevent the leg from turning toc far in the directionindicated inFig. II. In order to prevent it from turning too far in the otherdirection, and to preventlthe noise or unpleasant sound which wouldoccurif I depended upon the shoulders of the rule-joint 7 entirely, Iattach one or more cords 9 to the back side, which are attached by anysuitable method, so as to take the strain just before the Ashoulders ofthe joint come in contact; but if they should become loose', or for anycause fail to act, then the rule-joint will hold it,'so that no.accident can occur therefrom. At the lower end of B I insert a block,D, or filling, which makes the lower end solid. This block` or fillinghas a tenen, D, extending down -into a suitable mortise in the foot C,about halfway through it. The lower and back sides of this tenon arecovered by the plate of steel or other suitable metal 6, and is fittedat the lower end at an angle, as shown, and at its front end is curvedor bent so as to form c. joint with the cross-rod 5, as shown in Fig. V,which cross-rod extends through the foot, and has a buckskin or rubberlining or covering Z, so as to prevent noise and avoid frequentlubrication. This forms the pivot of the anklejoint, and is located nearthe centre of the foot, `as respects its length. I consider this centrallocation important, as Vit gives the leg a rm support and thefoot aneasy movement. i The lleel is supported and operated by therubber-spring 2, which is made of rubber-hose or pipe, and is secured inplace by the keys or wedges c, driven or pressed in at the top of theblock D and the bottom of. the heel', as'shown, asuitable hole beingpreviously made through the foot C and block D.- If it is desirable toelevate the toe when the step isbcing taken, then the spring 2 may bemade of compressed rubber or other suitable material, so as to throw theheel down. The front part of the foot is supported by the spring 3, alsomade of rubber or prepared rubber cloth, and wedged into a suitable holoat its upper end by the wedge j, andf secured at its lower end by thecross-bar or band In. This arrangement gives the foot an easy movement,and it is prevented from going too far by the front e of the mortise,into which the tenon D is inserted. The toe-joint is formedby the hinged, located on the upper side ofthe foot, and controlled by the steel.spring 4, whichis embedded in the bottom'of the foot, and firmlyattached to it at its ren-r end. Its front end is bent down so as toform the hook or -stop m, so'that by means of a cross-bar, z', which isattached near such hook or stop, and across the spring, the joint isprevented from yielding beyond the fixed point m, for when the cross-bar'i comes in contact with m the joint will not bend or open any further,andwhen relieved from pressure the spring will return the toes to theiroriginal position. The foot part is made solid,' except as cut andmortised, as indicated. The joint of the ankle may be made partly of theball-and-socket form, and covered, so as to prevent the hose, whenworin, from being caught'and cut or injured by the action of thejoint. i

The operation will be apparent from the description.

The nature of my invention consists `in constructing the upper and lowerportions A and B, or either of them, of alternate strips of thin woodand cloth, suitably'fastened together; in providing'the knee-joint withau adjustable rubber or other spring, to support it and return it to itsoriginal position in supporting the lower part of the leg upon ajointlocated centrally; in the manner of attaching the spring 2 by `thewedges Yc; in conliningthe movement of the toefjoint by means of a lockor stop at the end of the spring 4, and in tbe several combinationsherein set forth and claimed. j

Having thus fully described my artificial legs, what I claim as new, anddesire to secureby Letters Patent, is-

1. Constructing the -upper and lower portions'ot` an artificial leg Aand B, or either of them, of alternate strips of thin wood and cloth,substantially as and for the purposes specified.

2. The pivot 'of the ankle-joint, when located centrally as respects thelength of the foot, and constructed and operating substantially asspecified.

3 The combination and arrangement of the tenon D, plate 6, hinge-rod 5,and springs 2 and 3,'with the foot C and lower portion of the leg B,forming the ankle-joint, when constructed and operating substantially asspecified.

4. -The combination and arrangement of the spring-strap 1, knee-openingf, calf-opening h,'rulejoint 7, an the cords or lacing 9, with the upperportion A and lower portion B of the leg, forming the knee-joint, whenconstructed andoperating substantially as and for the purposesspecified.

i' FR. SCHMITT.

Witnesses:

L.' L. Bonn, E. A. WEST.

